two colors one border css code example
Example: double border color css
.double-border {
display: block;
clear: both;
background: red;
border: 5px solid yellow;
outline: 5px solid blue;
transition: 0.7s all ease-in;
height: 50px;
width: 50px;
}
.double-border:hover {
background: yellow;
outline-color: red;
border-color: blue;
}
<div class="double-border"></div>